How to block email on iPad

My mail works fine on my iPad. When I download my mail fromthe server, many junk mails will be coming. On my computer these get blocked through rules. How can I block sender on the mail app to filter out the junk emails.You cann't set rules for blocking spam or other unwanted mail on the iPad. You can set up the rules on the email server directly.There are some block email spam apps, but not good